And on this whistle, unleash chaos. Nobody really knows how Plymouth Argyle managed to survive those nine minutes of injury time at the end, those interminable minutes when hearts were pounding and nerves were shredding and it felt like not just Conor Hazard’s goal, not just Home Park, but Plymouth itself, was under siege.

Just as nobody had really seen this coming: the team rooted to the foot of the Championship, hosting perhaps the best team in the world right now, and sending them spectacularly to the canvas. Ryan Hardie’s penalty early in the second half was the difference between the sides, and even then nobody really believed. But as those nine minutes ticked away, one of the greatest shocks in the modern history of the FA Cup felt agonisingly close and agonisingly elusive all at once.

Related: ‘Maybe they deserve to be a bit lucky’: Slot defends lineup after Plymouth loss

And then the chaos. Home Park lifted off its hinges, a roar that carried all the way across the Riviera, a mess of limbs and lungs, memories that will last a lifetime. Callum Wright, the winger from Huyton who grew up on the same Bluebell Estate as ­Steven Gerrard, looked overcome with emotion. On the touchline, Arne Slot magnanimously shook the hand of Miron Muslic, the man who had just orchestrated this unlikeliest of underdog triumphs.

For Slot and his players there will be pressing questions to answer in the coming days, questions about selection and application, a ­weakened lineup that should still have got the job done. Instead Liverpool played like exactly what they were: a side that had barely played together before. For a team basically built on chemistry, understanding instincts honed and shared, this is a bigger problem than it would be somewhere else.

Luis Díaz and Diogo Jota struggled for rhythm against a rugged Plymouth back five. Federico Chiesa looked lost on the right wing. An early injury to Joe Gomez was suboptimal. Darwin Núñez offered little off the bench. And with the senior players rested, there was little firepower to add once the first wave had failed so comprehensively.

And all the while, the hills were alive with the sound of Muslic. The new Plymouth coach may have been in the job for a only month, but already he has infused the club with new belief, new vibes, new vigour. There is an alpha magnetism to the bearded Austrian, a coach who talks a lot about “courage” and “balls”, who looks like the sort of guy who will try to sell you a 12-part online course on how to unlock your inner wolf.

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But what Muslic gets – and what his predecessor Wayne Rooney largely did not – is that a club getting trampled on by bigger, richer rivals needs an idea. An ideal. A simple message that binds and inspires. There is so much here worth fighting for: a town and a region that lives for this club, that still fills Home Park most weeks to watch the worst football in the division. Muslic’s mission has been to recast Plymouth as a kind of last stand, a besieged turf to be defended at all costs.

In footballing terms, this means resolve, long balls, physicality, balls on the line. The new centre-half Maksym Talovyerov roared as he bodied Díaz and won a goal-kick. Nikola Katic, another new defender brought in from Zurich, lost a tooth in an early collision with a teammate. When informed about this on the touchline, Muslic laughed heartily.

For all this, and despite acquitting themselves well during a goalless first half, Plymouth are still a team short of confidence. The few chances were predictably fluffed, and so it was their great fortune when, as Darko Gyabi aimlessly hooked the ball back into the area on 51 minutes, Harvey Elliott charged across and handled it with raised arms. Hardie – a forward ­boasting just three goals in 24 league games this season – made no mistake. And suddenly, this was on.

An injury break allowed Slot some time to gather his players by the side of the pitch and dish out some truth bombs from his notebook. Isaac Mabaya, the debutant who had replaced Gomez in the 11th minute, was brutally pulled in the 58th for Núñez, one of only two senior players on the bench. The other, Curtis Jones, was barely fit and remained unused.

Still Liverpool looked utterly disjointed. Matthew Sorinola was heroic in the final stages, tackling Díaz just as he was about to finish. And yet for all the drama, the ­balance of chances was actually fairly even: one to James ­McConnell, one to Jota, a Núñez header in the 99th minute that was saved brilliantly by Hazard. At the other end Hardie, now cooking like prime R9, smashed the outside of the post after a fine save from Caoimhín Kelleher.

Related: Plymouth Argyle 1-0 Liverpool: FA Cup – live reaction

The aftermath was surreal and stirring in equal measure. ­Disbelieving Plymouth players posed for pictures, took their children to share the moment. As the stands finally emptied the seagulls arrived, baying and braying, circling the stadium in search of discarded chips and scraps of burger bun. But for once, they had missed the best of the feast.

For Liverpool the echoes of this game will continue into next week, and possibly well beyond. Will the slight scheduling respite be worth the humiliation, the stunted momentum, the realisation among their title rivals that Liverpool’s vaunted squad depth may not be all that it seems?

But perhaps all that can wait for now. Arguably this was the Cup’s biggest shock since Bradford City overturned a 2-0 lead at Stamford Bridge a decade ago. And these things matter. For so long now Plymouth have been a club fighting off not just relegation but resignation, the temptation simply to sigh and accept what life throws at you, the nagging doubt of whether any of this actually matters. Over 100 glorious sunlit minutes, this was their answer.